Leveraging Actinide Hydrolysis Chemistry for Targeted Th and U Separations using Amidoxime-Functionalized Poly(HIPE)s

Area of Science:

• Materials Science
• Radiochemistry
• Polymer Chemistry

Background:

• Polymerized high internal phase emulsions (poly(HIPE)s) offer tunable synthesis for incorporating functional units.
• Nitrile-containing polymers are versatile precursors for post-synthetic modifications.

Purpose of the Study:

• To synthesize nitrile-containing poly(HIPE)s using acrylonitrile (AN) or 4-cyanostyrene (4CS).
• To investigate the actinide uptake capabilities of amidoxime-functionalized poly(HIPE)s.
• To analyze the selectivity of these polymers for actinide separation.

Main Methods:

• Synthesis of nitrile-containing poly(HIPE)s.
• Post-synthetic modification to amidoximated analogues.
• Actinide adsorption studies using Th4+ and UO2 2+.
• High-energy X-ray scattering analysis.

Main Results:

• Amidoxime-functionalized poly(HIPE)s adsorbed 95% of Th4+ within 30 minutes.
• Uptake of UO2 2+ was lower compared to Th4+ under similar conditions.
• Polymer selectivity was attributed to the uptake of multinuclear Th clusters.

Conclusions:

• Amidoxime-functionalized poly(HIPE)s are effective for rapid thorium adsorption.
• These polymers exhibit selectivity for thorium over uranyl ions.
• High-energy X-ray scattering provides insights into the mechanism of actinide uptake and separation.